Copending Australian Patent Application No. 85296/91 describes a threaded fastener suitable for securing a grinding wheel to the spindle of an angle grinder. The fastener comprises a first disk-shaped component having a first pressure transmitting surface adapted to bear against the grinding wheel, and a second disk-shaped component having a threaded hub non-rotatably fixed thereto. The first and second components are assembled on the hub so as to be rotatable with respect to each other, and the second component is adapted to apply an axially directed compressive force to press the first component against the grinding wheel when a torque is applied to the second component. A solid dry lubricant washer is provided between the first and second components in an annular recess immediately adjacent the hub, for reducing friction, when one of the components is rotated relative to the other. The lubricant washer insures that a significantly increased proportion of the torque applied to the second component is converted to compressive force transmitted through the first component to the grinding wheel.
While the performance of the above-described threaded fastener is entirely satisfactory and represents a great advance upon the art, the second component is typically of complex design and, as it normally carries the full clamping pressure of the nut, must be made from metal. This requires either a complex NC-machining process or the use of sintered powder metallurgy. It would be desirable if a part with such a complex shape could be made from plastics material by injection moulding or by die-casting. In practice, it has also proved difficult for a user to judge whether the fastener has been adequately tightened, due to the fact that the turning friction normally associated with tightening has been substantially eliminated. There is thus a danger of overtightening of the fastener.